Details
| Original language | English |
|---|---|
| Article number | 204506 |
| Journal | Journal of Chemical Physics |
| Volume | 130 |
| Issue number | 20 |
| Publication status | Published - 2009 |
Abstract
Differential scanning calorimetry and density measurements were employed to study relaxation processes in compressed NaAlSi3 O8 and Na0.34 Ca0.31 Al0.96 Si3.04 O 8 glasses with negative dependence of viscosity () on pressure (p). Isobaric configurational heat capacities, coefficients of thermal expansion and compressibility of the melts, and real and apparent fictive temperatures are reported for the pressure regime from 0.1 to 700 MPa and cooling rates from 0.1 to 400 K/min. The onset of glass transition, measured on the compressed glass under normal pressure, is found to shift with increasing pressure of freezing in accordance with in situ viscosity data. Based on the pressure-derivative of the compression-induced excess enthalpy (or apparent fictive temperature), a condition for which a negative dependence of fictive temperature on pressure occurs is developed. It is further shown that in this case, also d/dp is negative. We suggest that in the region of glass transition, glasses with large Prigogine-Defay (PD) ratio have a high probability to also exhibit a negative dependence of viscosity on pressure. However, the criterion cannot be applied inversely: particularly glasses with a high sensitivity of short-range structural parameters to pressure may exhibit a relatively low PD ratio, but negative d/dp.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- General Physics and Astronomy
- Chemistry(all)
- Physical and Theoretical Chemistry
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In: Journal of Chemical Physics, Vol. 130, No. 20, 204506, 2009.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Relaxation and Prigogine-Defay ratio of compressed glasses with negative viscosity-pressure dependence
AU - Wondraczek, Lothar
AU - Krolikowski, Sebastian
AU - Behrens, Harald
N1 - Funding Information: Financial support by the Deutsche Forschungsgemeinschaft (DFG) under Grant No. WO 1220/3-1 is gratefully acknowledged.
PY - 2009
Y1 - 2009
N2 - Differential scanning calorimetry and density measurements were employed to study relaxation processes in compressed NaAlSi3 O8 and Na0.34 Ca0.31 Al0.96 Si3.04 O 8 glasses with negative dependence of viscosity () on pressure (p). Isobaric configurational heat capacities, coefficients of thermal expansion and compressibility of the melts, and real and apparent fictive temperatures are reported for the pressure regime from 0.1 to 700 MPa and cooling rates from 0.1 to 400 K/min. The onset of glass transition, measured on the compressed glass under normal pressure, is found to shift with increasing pressure of freezing in accordance with in situ viscosity data. Based on the pressure-derivative of the compression-induced excess enthalpy (or apparent fictive temperature), a condition for which a negative dependence of fictive temperature on pressure occurs is developed. It is further shown that in this case, also d/dp is negative. We suggest that in the region of glass transition, glasses with large Prigogine-Defay (PD) ratio have a high probability to also exhibit a negative dependence of viscosity on pressure. However, the criterion cannot be applied inversely: particularly glasses with a high sensitivity of short-range structural parameters to pressure may exhibit a relatively low PD ratio, but negative d/dp.
AB - Differential scanning calorimetry and density measurements were employed to study relaxation processes in compressed NaAlSi3 O8 and Na0.34 Ca0.31 Al0.96 Si3.04 O 8 glasses with negative dependence of viscosity () on pressure (p). Isobaric configurational heat capacities, coefficients of thermal expansion and compressibility of the melts, and real and apparent fictive temperatures are reported for the pressure regime from 0.1 to 700 MPa and cooling rates from 0.1 to 400 K/min. The onset of glass transition, measured on the compressed glass under normal pressure, is found to shift with increasing pressure of freezing in accordance with in situ viscosity data. Based on the pressure-derivative of the compression-induced excess enthalpy (or apparent fictive temperature), a condition for which a negative dependence of fictive temperature on pressure occurs is developed. It is further shown that in this case, also d/dp is negative. We suggest that in the region of glass transition, glasses with large Prigogine-Defay (PD) ratio have a high probability to also exhibit a negative dependence of viscosity on pressure. However, the criterion cannot be applied inversely: particularly glasses with a high sensitivity of short-range structural parameters to pressure may exhibit a relatively low PD ratio, but negative d/dp.
UR - http://www.scopus.com/inward/record.url?scp=66749132466&partnerID=8YFLogxK
U2 - 10.1063/1.3141382
DO - 10.1063/1.3141382
M3 - Article
AN - SCOPUS:66749132466
VL - 130
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 20
M1 - 204506
ER -